1. Technical Field
The present invention relates generally to motor vehicle drive systems; specifically, to electrically or internal combustion engine-powered vehicles that utilize regenerative powering of electrical drive motors.
2. State of the Art
Electrically powered drive systems are among the oldest drive systems for vehicles. Electric vehicles first came into existence in the nineteenth century, when electricity was a preferred method for automobile propulsion. Drivers of early electric motor-powered automobiles did not experience the vibration, smell, and noise associated with then-available internal combustion engines. Additionally, early electric vehicles did not require a transmission or starting by a hand-crank. These and other advantages of electric vehicles provided a level of comfort and ease of operation that could not be achieved by the gasoline-powered cars of the day.
Historically, however, electric vehicles also had disadvantages when compared to alternatives. Their range was relatively short and infrastructure required for recharging was limited. Between 1890 and 1920, gasoline became much more widely available and considerably cheaper than electricity. Advances in technology, such as invention of the assembly line and the electric starter motor, made internal combustion engine-powered vehicles cheaper to purchase and fuel, and ultimately easier to operate and maintain, than electric vehicles. By the late 1920s, the internal combustion engine had largely replaced electric motors for vehicle drive systems.
Over recent decades, and particularly since the millennium, electrically powered vehicle drive systems have been making a comeback. Advances in battery technology along with the negative environmental and social impacts associated with burning of fossil fuels is creating new opportunities for alternative vehicle power sources and drive mechanisms. Although present systems for powering electric vehicles, whether purely electric or gasoline-electric hybrids, have advanced considerably, they continue to have deficiencies, particularly with range and acceleration. Electric motor power sources often fail to provide sufficient power to satisfy many consumers. Kinetic energy of the moving vehicle is either completely wasted or inefficiently utilized, further limited range and acceleration.
Accordingly, an improved drive system for electrically powered vehicles is needed.